1. Field of the Invention
The present invention relates to electrical connectors, and more particularly to electrical connectors with anti-mismating structure for preventing standard USB plugs inserted therein.
2. Description of Related Art
Nowadays, Universal Serial Bus (USB) interface has been used as a standard input/output interface in variety of apparatus. Accordingly, electrical connectors can be designed to accord with the USB interface in order to transfer USB signals.
FIGS. 9 and 10 show existing USB connectors. In FIG. 9, this USB connector is an existing USB receptacle 300, female connector. In application, the USB receptacle 300 may be mounted on a board of a host device. The USB receptacle 300 presents a type-A USB connector. The USB receptacle 300 includes an insulative receptacle tongue portion 32, four conductive contacts 33 held on a bottom surface of the insulative receptacle tongue portion 32 and a metal shell 34 enclosing the conductive contacts 33 and the insulative receptacle tongue portion 32 to form a receiving cavity 36 formed therebetween. USB signals typically include power, ground (GND), and serial differential data D+, D−. To facilitate discussion, the four conductive contacts 33 are designated with numeral 331, 332, 333 and 334 in turn as shown in FIG. 9. In application, the four conductive contacts 331, 332, 333 and 334 are used to transfer power, D−, D+ and ground signals, respectively.
FIG. 10 shows an existing USB plug 400, male connector. The USB plug 400 also presents a type-A USB connector and is usually disposed in the peripheral device to be inserted into the USB receptacle 300. The USB plug 400 comprises a plug tongue portion 42 with four conductive contacts 43 retained thereon and a metal shell 44 enclosing the plug tongue portion 42 and the four conductive contacts 43. The metal shell 44 touches the insulative plug tongue portion 42 on three of the surfaces thereof except a top surface 46 on which the conductive contacts 43 are supported. Same to assignment of the four conductive contacts 33 of the USB receptacle 300, assignment of the four conductive contacts 43 of the USB plug 400 is contact 431 for power signal, contact 432 for D− signal, contact 433 for D+ signal and contact 434 for GND.
After fully insertion of the USB plug 400 into the receiving cavity 36 of the USB receptacle 300, the conductive contacts 431, 432, 433 and 434 of the USB plug 400 make a physical and electrical connection with the conductive contacts 331, 332, 333 and 334 of the USB receptacle 300, respectively, to transmit/receive signals to/from the host device to the peripheral device.
Under special circumstances, a type of special electrical connectors are needed to transfer signals which are similar to while not compatible to the standard USB signals. The special electrical connectors are similar to the standard USB connectors so that the special electrical connectors can be easily manufactured by a little improvement of the existing USB mold in order to decrease the cost of manufacture. However, since the special electrical connectors are similar to the standard USB connectors, there is a need that the special electrical connectors designed with anti-mismating structures to prevent the standard USB connectors inserted therein.